The display of pre-packaged food and other products commonly involves the use of adjustable width trays with spring-driven pushers for moving a column of packages forward as items are removed from the front of the tray. Adjustable side guides are provided for confining the packages in a desired column form as individual packages are withdrawn from the display. A critically important aspect of such package displays is the ability of maximize the number of such display trays in a given display area and also to maximize the effective length of the tray to enable stocking with as many packages as possible. This is especially true where the display trays are mounted in a fully confined space such as coolers with front walls or doors. The above-mentioned application Ser. No. 12/354,498 discloses a novel form of display tray that represents a significant improvement over earlier trays in, among other things, utilizing its adjustable side guides to provide cantilever mounting of the tray on a display bar. Notwithstanding the benefits and advantages of the above described tray, there is still room for improvement in further optimizing the space efficiency of the tray and its supporting means.